By fairly good, I assume you mean pretty amazing.
I've watched a lot of Japanese anime, so I've picked up the odd line or two in Japanese. Apart from that, the only Japanese I know, stems from Karate - different names of punches and kicks, stances, blocks, katas and whatnot. I sometimes train with a Japanese instructor so I have witnessed some of the behaviour patters that the Japanese generally express. It's a bit hard to explain but they are a bit different from . . . the rest of the world.